diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp index da76f5b3d498a..78d0887d5d87e 100644 --- a/llvm/lib/Analysis/Loads.cpp +++ b/llvm/lib/Analysis/Loads.cpp @@ -631,9 +631,13 @@ static Value *getAvailableLoadStore(Instruction *Inst, const Value *Ptr, if (!Val || !Len) return nullptr; - // TODO: Handle offsets. - Value *Dst = MSI->getDest(); - if (!AreEquivalentAddressValues(Dst, Ptr)) + // Handle offsets. + int64_t StoreOffset = 0, LoadOffset = 0; + const Value *StoreBase = + GetPointerBaseWithConstantOffset(MSI->getDest(), StoreOffset, DL); + const Value *LoadBase = + GetPointerBaseWithConstantOffset(Ptr, LoadOffset, DL); + if (StoreBase != LoadBase || LoadOffset < StoreOffset) return nullptr; if (IsLoadCSE) @@ -645,7 +649,7 @@ static Value *getAvailableLoadStore(Instruction *Inst, const Value *Ptr, // Make sure the read bytes are contained in the memset. uint64_t LoadSize = LoadTypeSize.getFixedValue(); - if ((Len->getValue() * 8).ult(LoadSize)) + if ((Len->getValue() * 8).ult(LoadSize + (LoadOffset - StoreOffset) * 8)) return nullptr; APInt Splat = LoadSize >= 8 ? APInt::getSplat(LoadSize, Val->getValue()) diff --git a/llvm/test/Analysis/GlobalsModRef/memset-escape.ll b/llvm/test/Analysis/GlobalsModRef/memset-escape.ll index 77652a6278aae..0bdc4152de1c9 100644 --- a/llvm/test/Analysis/GlobalsModRef/memset-escape.ll +++ b/llvm/test/Analysis/GlobalsModRef/memset-escape.ll @@ -7,23 +7,14 @@ target triple = "x86_64-apple-macosx10.10.0" @a = internal global [3 x i32] zeroinitializer, align 4 @b = common global i32 0, align 4 -; The important thing we're checking for here is the reload of (some element of) -; @a after the memset. +; The important thing we're checking here is that the value from the memset +; rather than the preceding store is forwarded. define i32 @main() { ; CHECK-LABEL: define noundef i32 @main( ; CHECK-SAME: ) local_unnamed_addr #[[ATTR0:[0-9]+]] { ; CHECK-NEXT: [[ENTRY:.*:]] -; CHECK-NEXT: store i32 1, ptr getelementptr inbounds nuw (i8, ptr @a, i64 8), align 4 -; CHECK-NEXT: tail call void @llvm.memset.p0.i64(ptr noundef nonnull align 4 dereferenceable(12) @a, i8 0, i64 12, i1 false) ; CHECK-NEXT: store i32 3, ptr @b, align 4 -; CHECK-NEXT: [[TMP0:%.*]] = load i32, ptr getelementptr inbounds nuw (i8, ptr @a, i64 8), align 4 -; CHECK-NEXT: [[CMP1_NOT:%.*]] = icmp eq i32 [[TMP0]], 0 -; CHECK-NEXT: br i1 [[CMP1_NOT]], label %[[IF_END:.*]], label %[[IF_THEN:.*]] -; CHECK: [[IF_THEN]]: -; CHECK-NEXT: tail call void @abort() -; CHECK-NEXT: unreachable -; CHECK: [[IF_END]]: ; CHECK-NEXT: ret i32 0 ; entry: diff --git a/llvm/test/Transforms/InstCombine/load-store-forward.ll b/llvm/test/Transforms/InstCombine/load-store-forward.ll index 9a5db318df5e7..0f03f16062e52 100644 --- a/llvm/test/Transforms/InstCombine/load-store-forward.ll +++ b/llvm/test/Transforms/InstCombine/load-store-forward.ll @@ -365,13 +365,10 @@ define i32 @load_after_memset_unknown(ptr %a, i8 %byte) { ret i32 %v } -; TODO: Handle load at offset. define i32 @load_after_memset_0_offset(ptr %a) { ; CHECK-LABEL: @load_after_memset_0_offset( ; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr noundef nonnull align 1 dereferenceable(16) [[A:%.*]], i8 0, i64 16, i1 false) -; CHECK-NEXT: [[GEP:%.*]] = getelementptr i8, ptr [[A]], i64 4 -; CHECK-NEXT: [[V:%.*]] = load i32, ptr [[GEP]], align 4 -; CHECK-NEXT: ret i32 [[V]] +; CHECK-NEXT: ret i32 0 ; call void @llvm.memset.p0.i64(ptr %a, i8 0, i64 16, i1 false) %gep = getelementptr i8, ptr %a, i64 4 @@ -379,6 +376,41 @@ define i32 @load_after_memset_0_offset(ptr %a) { ret i32 %v } +define i32 @load_after_memset_1_offset(ptr %a) { +; CHECK-LABEL: @load_after_memset_1_offset( +; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr noundef nonnull align 1 dereferenceable(16) [[A:%.*]], i8 1, i64 16, i1 false) +; CHECK-NEXT: ret i32 16843009 +; + call void @llvm.memset.p0.i64(ptr %a, i8 1, i64 16, i1 false) + %gep = getelementptr i8, ptr %a, i64 4 + %v = load i32, ptr %gep + ret i32 %v +} + +define i1 @load_after_memset_0_offset_i1(ptr %a) { +; CHECK-LABEL: @load_after_memset_0_offset_i1( +; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr noundef nonnull align 1 dereferenceable(16) [[A:%.*]], i8 0, i64 16, i1 false) +; CHECK-NEXT: ret i1 false +; + call void @llvm.memset.p0.i64(ptr %a, i8 0, i64 16, i1 false) + %gep = getelementptr i1, ptr %a, i64 12 + %v = load i1, ptr %gep + ret i1 %v +} + +define i8 @neg_load_after_memset_0_neg_offset(ptr %a) { +; CHECK-LABEL: @neg_load_after_memset_0_neg_offset( +; CHECK-NEXT: [[GEP:%.*]] = getelementptr i8, ptr [[A:%.*]], i64 2 +; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr noundef nonnull align 1 dereferenceable(16) [[GEP]], i8 0, i64 16, i1 false) +; CHECK-NEXT: [[V:%.*]] = load i8, ptr [[A]], align 1 +; CHECK-NEXT: ret i8 [[V]] +; + %gep = getelementptr i8, ptr %a, i64 2 + call void @llvm.memset.p0.i64(ptr %gep, i8 0, i64 16, i1 false) + %v = load i8, ptr %a + ret i8 %v +} + define i32 @load_after_memset_0_offset_too_large(ptr %a) { ; CHECK-LABEL: @load_after_memset_0_offset_too_large( ; CHECK-NEXT: call void @llvm.memset.p0.i64(ptr noundef nonnull align 1 dereferenceable(16) [[A:%.*]], i8 0, i64 16, i1 false)